In recent years, information terminal equipment including personal computers and servers, and communication equipment such as Internet routers and optical communication have been required to process massive information at high speed, and the speed and frequency of electrical signals have become higher. With this, in addition to conventionally required characteristics such as flame retardancy, heat resistance, and peel strength with copper foil and the like, a lower dielectric constant and a lower dielectric loss tangent have been required for printed wiring board materials used in the equipment. In order to meet these characteristic requirements, various attempts have been made in the configurations of resin compositions.
In order to provide electrical characteristics to such materials, a method of containing, in a resin composition, a resin having a low dielectric constant and a low dielectric loss tangent such as a fluororesin, a cyanate resin, a polyphenylene ether resin, or a vinyl compound mainly comprising styrene is known (for example, see Patent Literature 1). Generally, a laminate using such a compound has poor flame retardancy, and therefore in order to provide flame retardancy, it is necessary to contain a halogen-based compound in a resin composition (for example, see Patent Literatures 2 and 3). However, when a halogen-based compound is used, environmental problems arise, for example, harmful substances such as dioxin may be generated during burning.
Therefore, as methods for achieving flame retardancy without comprising any halogen compound at all, for example, studies of adding compounds mainly comprising phosphorus or nitrogen are made (for example, see Patent Literatures 4 to 8).